Intermittent androgen suppression in prostate cancer: the Canadian experience

The role of androgen withdrawal is well established in the treatment of advanced prostate cancer. In metastatic cancer the response rate is 70% to 80%, with a median duration of progression-free survival of 12 to 33 months and a median duration of overall survival of 23 to 37 months. There are limitations to the continuous use of androgen withdrawal therapy, including significant adverse effects with long-term use. More significantly, the cell death process induced by androgen ablation fails to eliminate the entire malignant cell population; recurrent tumors are characterized by androgen-independent growth. The concept of intermittent androgen suppression proposes that the maintenance of apoptotic potential by successive rounds of androgen withdrawal and replacement might forestall tumor progression. Intermittent therapy offers quality-of-life benefits during the off-therapy period, as well as reduced cost of treatment. This article will review the >15 years of Canadian experience with intermittent androgen suppression.